1) Field of the Disclosure
The disclosure relates generally to systems and methods for injecting fluids, and more specifically, to a liquid injector and associated propulsion system and method for injecting a premixed liquid propellant into a combustion chamber of a combustion engine, such as a rocket combustion engine.
2) Description of Related Art
Propulsion systems of air vehicles with rocket combustion engines, such as launch vehicles with liquid propellant rocket engines, may typically use single fluid injectors to inject and supply a fuel and an oxidizer into the combustion chambers of the engines. Mixing of the fuel and oxidizer occurs within the combustion chamber.
One known propulsion system separates the fuel and the oxidizer into two separate tanks and feed systems, such as liquid oxygen and liquid hydrogen, and mixes them in the combustion chamber just prior to ignition. However, such a separated propulsion system may suffer from the structural design weight penalty of having multiple tanks and feed systems. This may lower the mass fraction (propellant to total system weight) of such design.
Another know propulsion system may use a single molecule or a monopropellant, such as hydrazine, stored in one tank. Monopropellants are chemically structured such that if they are run through a catalyst bed, the monopropellant molecules dissociate. In so doing, they release their atomic bonding energy and produce heat. This provides the expansion pressures for thrust. Hydrazine (mono-methyl-hydrazine) has properties that allow it to act as both a monopropellant and as a fuel when combined with nitrogen tetroxide oxidizer (MMH/NTO). However, the use of monopropellants may be expensive and may require costly special suites and handling equipment.
Another known propulsion system may use a gaseous nitrous oxide fuel blend engine (e.g., premixed gas nitrous oxide/ethylene (N2O/C2H4)), with a micro-fluidic porous media element for anti-flashback. However, the premixed gas nitrous oxide/ethylene utilizing micro-fluidic porous media elements may restrict mass flow, as such micro-fluidic porous media elements use holes of fifty (50) microns and smaller to prevent flashback and do not offer the desired flow rate of fuel and oxidizer into the ignition combustion chamber. In addition, tuning this system has proven problematic and may introduce a limit to the propulsion thrust class.
Accordingly, an improved propulsion system and method for combustion engines, such as rocket combustion engines, is needed that provide advantages over known systems and methods.